Lin-Yen Wang

Cooperating mutations of receptor tyrosine kinases and Ras genes in childhood core-binding factor acute myeloid leukemia and a comparative analysis on paired diagnosis and relapse samples

c-KIT mutations have been described in core-binding factor (CBF) acute myeloid leukemia (AML) at diagnosis. The role of c-KIT mutations in the relapse of CBF–AML is not clear. The role of CSF1R mutation in the pathogenesis of AML remains to be determined. We analyzed receptor tyrosine kinases (RTKs) and Ras mutations on 154 children with AML. Also, we examined the paired diagnosis and relapse samples in CBF–AML. CBF–AML accounted for 27% (41/154). c-KIT mutations were detected in 41.5% of CBF–AML at diagnosis (6 in exon 8, 10 in exon 17 and 1 in both exons 8 and 17) , FLT3–TKD 2.7%, N-Ras mutations 7.3% and K-Ras mutations 4.9%. FLT3–LM and CSF1R mutations were not found in CBF–AML. The mutations of RTKs and Ras were mutually exclusive except for one patient who had both c-KIT and N-Ras mutations. Eight of the 41 CBF–AML patients relapsed; four patients retained the identical c-KIT mutation patterns as those at diagnosis, the remaining four without c-KIT mutations at diagnosis did not acquire c-KIT mutations at relapse. Our study showed that 54% of childhood CBF–AML had RTKs and/or Ras mutations; c-KIT but not CSF1R mutations play a role in the leukemogenesis of childhood CBF–AML.

Long-term results of Taiwan Pediatric Oncology Group studies 1997 and 2002 for childhood acute lymphoblastic leukemia

The long-term outcome of 1390 children with acute lymphoblastic leukemia (ALL), treated in two successive clinical trials (Taiwan Pediatric Oncology Group (TPOG)-ALL-97 and TPOG-ALL-2002) between 1997 and 2007, is reported. The event-free survival improved significantly (P=0.0004) over this period, 69.3±1.9% in 1997–2001 to 77.4±1.7% in 2002–2007. A randomized trial in TPOG-97 testing L-asparaginase versus epidoxorubicin in combination with vincristine and prednisolone for remission induction in standard-risk (SR; low-risk) patients yielded similar outcomes. Another randomized trial, in TPOG-2002, showed that for SR patients, two reinduction courses did not improve long-term outcome over one course. Decreasing use of prophylactic cranial irradiation in the period 1997–2008 was not associated with increased rates of CNS relapse, prompting complete omission of prophylactic cranial irradiation from TPOG protocols, beginning in 2009. Decreased use of etoposide and cranial irradiation likely contributed to the low incidence of second cancers. High-risk B-lineage ALL, T-cell, CD10 negativity, t(9;22), infant, and higher leukocyte count were consistently adverse factors, whereas hyperdiploidy >50 was a consistently favorable factor. Higher leukocyte count and t(9;22) retained prognostic significance in both TPOG-97 and TPOG-2002 by multivariate analysis. Although long-term outcome in TPOG clinical trials is comparable with results being reported worldwide, the persistent strength of certain prognostic variables and the lower frequencies of favorable outcome predictors, such as ETV6-RUNX1 and hyperdiploidy >50, in Taiwanese children warrant renewed effort to cure a higher proportion of patients while preserving their quality of life.

FLT3-TKD mutation in childhood acute myeloid leukemia

Mutations of receptor tyrosine kinases are implicated in the constitutive activation and development of human hematologic malignancies. An internal tandem duplication (ITD) of the juxtamembrane domain-coding sequence of the FLT3 gene (FLT3-ITD) is found in 20–25% of adult acute myeloid leukemia (AML) and at a lower frequency in childhood AML. FLT3-ITD is associated with leukocytosis and a poor prognosis, especially in patients with normal karyotype. Recently, there have been three reports on point mutations at codon 835 of the FLT3 gene (D835 mutations) in adult AML. These mutations are located in the activation loop of the second tyrosine kinase domain (TKD) of FLT3 (FLT3-TKD). The clinical and prognostic relevance of the TKD mutations is less clear. To the best of our knowledge, there has been no report to describe FLT3-TKD mutations in childhood AML. In this pediatric series, FLT3-TKD mutations occurred in three of 91 patients (3.3%), an incidence significantly lower than that of FLT3-ITD (14 of 91 patients, 15.4%) in the same cohort of patients. None of them had both FLT3-TKD and FLT3-ITD mutations. Sequence analysis showed one each of D835 Y, D835 V, and D835 H. Of the three patients carrying FLT3-TKD, two had AML-M3 with one each of L- and V-type PML-RARα, and another one had AML-M2 with AML1-ETO. None of our patients with FLT3-TKD had leukocytosis at diagnosis. At bone marrow relapse, one of the four patients examined acquired FLT3-ITD mutation and none gained FLT3-TKD mutation.

Recombinant Urate Oxidase (Rasburicase) for the Prevention and Treatment of Tumor Lysis Syndrome in Patients with Hematologic Malignancies

In this multicenter, nonrandomized, open-label clinical trial conducted from July 2003 to July 2004, recombinant urate oxidase (rasburicase) was administered to patients at risk for tumor lysis syndrome before or during the initiation of chemotherapy. Forty-five patients were enrolled, including 18 children (10 with acute lymphoblastic leukemia, 6 with high-grade lymphoma, and 2 with acute myeloid leukemia) and 27 adults (8 with acute lymphoblastic leukemia, 4 with high-grade lymphoma, 9 with multiple myeloma, and 6 with acute myeloid leukemia). The age ranged from 3 to 98 years, with a median age of 7 years in children and 59.3 years in adults. There were 14 males and 4 females in the pediatric group and 18 males and 9 females in the adult group. Rasburicase 0.2 mg/kg was administered intravenously once a day for 2–6 days, for a median of 3 days in children and of 4 days in adults. After 3 days of treatment, the median uric acid levels in the 18 children decreased from 10.5 mg/dl (range 8–18.6) to 0.5 mg/dl (range 0.0–1.7). Similarly, in the 27 adults, the median levels decreased from 10.8 mg/dl (range 8–24.4) to 0.5 mg/dl (range 0.0–1.6). No significant changes were observed in serum potassium, calcium, and phosphorus concentrations. None of the patients required dialysis for acute renal failure. Rasburicase was very well tolerated, with only 1 adult having grade 1 vomiting. We conclude that rasburicase is safe and highly effective for preventing the complications of tumor lysis syndrome in patients with hematologic malignancies.

CEBPα mutations in childhood acute myeloid leukemia

CEBPα mutations have been described in adult acute myeloid leukemia (AML) and conferred a favorable prognosis. However, CEBPα mutation has not been reported in children. We investigated 117 children with de novo AML using DNA PCR assay followed by sequencing for each PCR product. CEBPα mutations were detected in seven patients, four had FAB M2, two M1 and one M4. CEBPα mutations only occurred in patients with intermediate cytogenetics and not in 56 children with AML1-ETO, CBFβ-MYH11, PML-RARα or MLL rearrangements. Five patients had mutations occurred in both N-terminal part and basic-leucine zipper (bZIP) domain, one had an N-terminal frameshift mutation and the remaining one had an inframe insertion in the bZIP domain. Cloning analysis on five samples carrying more than one mutations demonstrated one homozygous combined mutations and four heterozygous biallelic mutations. Four of seven CEBPα mutation(+) patients had cooperating mutations with FLT3-ITD or N-ras mutations compared to 27 in 109 CEBPα mutation(−) patients. Our results showed that CEBPα mutations occurred in 6% of childhood AML and most exhibited combined mutations in both N-terminal part and bZIP domain.

CEBPalpha mutations in childhood acute myeloid leukemia.

CEBPα mutations have been described in adult acute myeloid leukemia (AML) and conferred a favorable prognosis. However, CEBPα mutation has not been reported in children. We investigated 117 children with de novo AML using DNA PCR assay followed by sequencing for each PCR product. CEBPα mutations were detected in seven patients, four had FAB M2, two M1 and one M4. CEBPα mutations only occurred in patients with intermediate cytogenetics and not in 56 children with AML1-ETO, CBFβ-MYH11, PML-RARα or MLL rearrangements. Five patients had mutations occurred in both N-terminal part and basic-leucine zipper (bZIP) domain, one had an N-terminal frameshift mutation and the remaining one had an inframe insertion in the bZIP domain. Cloning analysis on five samples carrying more than one mutations demonstrated one homozygous combined mutations and four heterozygous biallelic mutations. Four of seven CEBPα mutation(+) patients had cooperating mutations with FLT3-ITD or N-ras mutations compared to 27 in 109 CEBPα mutation(−) patients. Our results showed that CEBPα mutations occurred in 6% of childhood AML and most exhibited combined mutations in both N-terminal part and bZIP domain.

Triple intrathecal therapy without cranial irradiation for central nervous system preventive therapy in childhood acute lymphoblastic leukemia

To evaluate the treatment results of central nervous system preventive therapy (CNSP) with triple intrathecal therapy (TIT) alone in children with acute lymphoblastic leukemia (ALL).

Primary autoimmune neutropenia in children in Taiwan.

BACKGROUND: Autoimmune neutropenia in children is caused by granulocyte‐specific autoantibodies. These antibodies react to the patients own neutrophils but disappear when the neutropenia spontaneously remits. This study reviewed our experience with autoimmune neutropenia in children and investigated possible associations with HLA‐DR and HLA‐DQ alleles.

Long-term Treatment Results of Hepatoblastoma at a Single Institution in Taiwan

From 1990 to 2004, there were 23 consecutive patients with hepatoblastoma treated at Mackay Memorial Hospital in Taipei, Taiwan. There were 7 patients of stage I, 3 of stage II, 13 of stage III, and none had stage IV disease. Two siblings had congenital hepatoblastoma and both survived. Two patients were prematurity. Beckwith-Wiedemann syndrome, isosexual precocity, chronic B hepatitis presented in 1 patient each. In addition to surgery, we used cisplatin 90 mg/m2/d on day 1 and epirubicin 25 mg/m2/d for days 1 to 3 as first-line chemotherapy. Each course was repeated every 3 weeks. Epirubicin was chosen because of its lower cardiotoxicity. Carboplatin/etoposide and vincristine/cyclophosphamide/5-fluorouracil were the second-line chemotherapy for considering cumulative toxicity of first-line chemotherapy. If initial total excision was feasible, postoperative chemotherapy of 4 to 6 courses were given. Three patients died of progressive disease, infection, and relapse 1 each. The median duration of follow-up for 20 survived patients was 94 months. The 5-year event-free and overall survival rates were 73.9%±9.2% (SE) and 87%±7.0%, respectively. Tumor recurred in 5 patients. The commonest toxicity was febrile neutropenia. There was no cardiotoxicity event. In conclusion, with sequential combination of surgery and chemotherapy, the treatment results for hepatoblastoma were satisfactory as compared with other groups.

Invasive fungal infection in children undergoing chemotherapy for cancer

Abstract Background: In children with cancer, invasive fungal infection is a serious complication of anticancer therapy. Successful treatment is a major challenge for clinical oncologists. Methods: The records of all episodes of invasive fungal infection occurring in children with cancer undergoing chemotherapy at Mackay Memorial Hospital, Taipei between January 1987 and October 2005 were reviewed. The following were documented: general characteristics, clinical presentation, predisposing factors, pathogens, antifungal treatment, association with anticancer therapy and outcome. We endeavoured to preserve renal function by administration of new antifungal agents. Anticancer therapy was given as soon as possible after diagnosis and the dose of chemotherapeutic agents was adjusted as required to prevent unduly prolonged interruption of chemotherapy and minimise the risk of leukaemia relapse. Results: Twenty-six patients with 29 episodes of invasive fungal infection were reviewed. Candida species were the leading pathogens (14/29) followed by Aspergillus species (11/29). In six episodes there was both visceral dissemination and fungaemia. In 23/29 patients, antibiotic therapy preceded fungal infection with a median of 11 days. Three children died from extensive fungal infection and four from progression of malignancy; the remainder survived with a median follow-up of 40 months (range 12–233). The actuarial 12-month survival rate was 87%; in patients with invasive candidiasis and aspergillosis the rates were 75% and 100%, respectively. Conclusions: In children with cancer, most invasive fungal infections can be treated successfully. Current antifungal prophylaxis should protect patients from fungal infection.